Core drill



Patented Dec. l,A 1925.- i

UNITED STATES-"PATENT oFFi-CE.

ROLAND R. cnUM, or WHITTIER, CALIFORNIA.

CORE DRILL.

Application led August 12, 1922. lSerial No. 581,431.

R. CRUM, a

' core drill in which` the core receiving barrel and the core bit are removable as a unit.

A further object is to provide `a core drill in which the water displaced from the core receiving barrel by the core, is directed downwardly along the outer surface of said barrel to maintain the core barrel at a temperature which will eliminate a burning of the core by the friction of the rotating bar-A rel against the stationary core.

Another object is to provide acoie drill in which the circulation water is prevented from passing directly into the upper end of the core barrel;- and to provide a drill in which Vthe water displaced from the core receiving barrel is kept separate from the circulation water and discharged directly into the drill bore.

Another object is to provide a core drill having a central core receiving` barrel, a discharge chamber surrounding the barrel, and a circulation chamber surrounding the dis? charge chamber, the discharge chamber being closed to communication with the circulation chamber and communicating directly with the drill bore, whereby water displaced from the core barrel' by the core is directed into one end of the ldischarge chamber .and is discharged from the p charge chamber directly into the drill bore, independently of the circulation water.

A further object is to provide la core drill having a core receiving barrel provided with valve means at its upper end to permit an exit of Water displaced by the core, there being a discharge chamber communicating directly with the drill bore and enclosing the barrel and valve means, whereby the valve is not subjected to the pressure of the circulation water. y

Another object resides in the provision of an improved form of outer boring bits.

-rel there is a tendency other end of said disi In withdrawing the drill and the core barto produce a suction at the lower end of the core barrel which sometimes operates to withdraw the core so that it becomes lost. One of the objects of this invention is to provide means for preventing the loss of the core' in this way.l

be more fully apparent from the following description of the accompanying drawings, which forma part of this disclosure, and which illustrate a preferred form of em- Various other objects and advantages will `bodiment of the invention.

Of the drawings: Figure 1 is an elevation core drill.

Fig. 2 is a bottom plan view. Fig. 3 is an enlarged vertical section. l Fig.A 4 is a plan section on line 4-4 of rig. l v Fig. gis a detail elevation vof cutter supporting body member.

Fig. 6 is a section on line 6-6 of Fig. 5, looking upwards.

Fig.

of my improved 1s a perspective view of the cutter supporting body member and` the elements carried` thereby, removed from the main body member.

Fig. 8 is a perspective view of .one of thev outer boring cutters.

F igt 9 is a vertical section of the lower portion of the drill, in operating position in a drill bore, and

Fig. l0 is a detail view of a modified form of core bit construction. i

In prospecting mineral fields core drills are often employed for the purpose ofobtaining samples of undergrouhd formations, and in drilling wells, -particularly oil wells, it is oftendesirableto obtain samples of the form tion for the purpose of obtaining a record of the various strata encountered, and in providing ai core drill for these purposes which will successfully function in* the various types of formation, certain re- 100 quirements must be rigidly adhered to. As a drill of this character is ordinarly operated in the presence of circulating flushing water which carries the4 cuttings to the surface, it will be evident that the core, espe- 105 cially when operating in soft or` sand formations must be effectively protected againstI `t-he flushing action of the water, and further as the rotative action of the drill against the stationary core is productive o'f friction u@ f which has 'a tendency to burn the corev it is important that provisions be made for coolcore is subjected to the full pressure of such water. This, I have found to be of considerable detriment to Aspeedy operation a'nd to,

the obtaining ofperfect cores, therefore,-in the present invention I provide means for preventing direct communication 'between thecirculating chamber and the end of the core barrel, and furthermore the core barrel` and core barrel discharge is entirely independent of the water circulating system.

Referring to the drawings, the body of the drill consists of a main tubular body member 1 attached to the drillstring, and providing a water circulation chamber Q,

and a lower cutter supporting member 3 screw-threaded .into the lower. end of 'the member 1. I provide means for preventing communication between the circulation chamber and the upper end of the core barrel. For this purposethe member 3 carries a tubular member 4 projecting upwardly into the chamber 2 of the body and providing a discharge chamber 5 which is closed at its upper'end and hasno communication with the chamber 2.

core barrel 6 has a screw-threaded engagement into the lower end of the body member 3 and extends upwardly into the chamber 5, the bore of the body member 3 vthroughout amaj or portion of its length being slightly larger than the exterior diameter of the core barrel 6, so as to provide arel stricted extension 7 of thedischarge chamber 5. When the drill is pulled upwardly there is a tendency toproduce a par'- tial vacuum in the core barrel 6 which might pull out thecore. In order to prevent this I provide means for balancing the partial vacuum, that is to say, I provide a construction whereby a partial vacuum will be formed in the chamber 5 as well as within the core barrel. For this purpose'I provide the body member 3 with discharge ports S communicating with said chamber extension 7 and discharging fluid from the chamber 5 directly into the drill bore. These discharge ports preferably incline downwardly (see Figure 3) as this direction increases the effect in forming the partial vacuum in the extension 7 which communicates with the discharge chamber .5. These ports therefore perform two functions.

The upper end of the core barrel 6 carries a plug member 9 having ports 10 and a closurein the form of a disc 11 slidable on a headed stem 12 xed in the plug member, normally closes the ports 10 under the iniuenceof a`spring 13.

The valve 11 sits directly on the end of the barrel and the space around its edge is not obstructed in any way, and hence if thc valve-disc is off its seat at all, it will operate to open communication between the chamber space 5 and the interior of the core barrel.

The lower extension 14 of the core barrel carries a tubular core bit 15 whose bore registers with the bore of the core barrel, the lower edge of said bit being provided with -radially disposed cutting teeth 16.

The body member 3 is provided with two opposed outer boring cutters 17, the member `3 being cut away, as at 18,'to provide clearance for `the cuttings and for theaction of the flushing water, and recessed as at 19 to receive the Shanks of the cutters 17.

`The cutters 17 have horizontal dove-tail webs or tongues 20 and the member 3 has corresponding dove-tail ways 21 whereby the cutters maybe laterally slid into place, each cutter being rigidly secured by a bolt 22 extending through a bore 23 in the body member 3 and screw-threaded into the cutter shank.' f

The cutter 17 are oppositely angled relative to the iertical and extend below the lower surface of the member 3 with their cutting edges angled outwardly and backwardly relative to\the direction of rotation so as to urge the cuttings towards the outer periphery of the drill, each of said cutters 17 and each of .the teeth 16 of the core bit 15 being provided with proper relief rearwardly of their-cutting edges to produce an efficient cutting-action.

Extending downwardly from the rupper surface of the member 3 are circulation ducts 24 which terminate adjacent the shai'iks of the respective cutters 17 and di- ,rect the flushing water along the forward faces of said cutters.

In Figure 10 of the drawings, I have illustrated a modified form of structure in which the core bit 15a is screw-threaded directly into the lower end of the body member 3, and the core barrel 68L is screwthreaded directly into the upper end of the core bit. This structure may be conveniently used in instances where it is not desirable to have the core bit extend much beyond the lower ends ofthe outer boring cutters.

valve 11 and flowinglinto the discharge chamber 5 from which it discharges through the ports 8 into the drill bore. As the chamber 5 :and extension 7 thereof surround the core barrel throughout nearly its full length `it will be evidentthat in such an arrangement an effective means has been provided for cooling the core barrel so as to eliminate any danger ofkxburning the core.

will be plain that, with the core barrel entirely enclosed within the tubular member 4 which has .no communication with the circulation chamber 2, the core barrel 6 and its valve 11, and the core, when the valve ll is opened, are not subjected to the pressure of the circulation water and for this reason the valve will have a more free action and the core will lbe entirely removed 'from' the flushing action of the circulation water. s

A particular ladvantage incident to the arrangement of the independent discharge chamber, resides in the suction action it produces on a core withinl the core barrel in the event that the valve 11 for any reason fails to close tightly during the withdrawal of the drill. During such withdrawal, the

vacuum inuence created below the drill will have a tendency to draw the core out of the core barrel, and in case the valve 1l does not closethe core will be quite easily sucked rom the core barrel, especially where `the core is 'somewhat loose in the barrel.

Be reason of the arrangement of the discharge chamber and its discharge ports this loss pf the core is prevented, as the suction, actingthrough the ports 8, chamber 5, and improperly seated valve 11, will act on the top of the core, and in this manner counteract the suction influence on the bottom ofthe core, this counteraction effectively preventing a loss of the core.

Vith the construction illustratedthe core barrel and`valve as a unit may be convenient-ly removed from the drill without disturbing the outerv cutters 'orany of itsother parts, also,the body member 3` carrying` all the parts of the drill excepting the tubular body member l, may be removed in a downward direction from said body member 'l as a complete unit so the core` barrel .maybe removed independently of thetouter'cutters.

The disc or closure 11 is not of larger diameter than the barrel 6 and thus enables the barrel to be withdrawn through the lower end of the bit.

While the specific form of mechanism 'herein disclosed is well adapted to fulfil the objects primarily stated, it is t0` be understood that I do not wish to limit the invention to the form of embodiment herein illustrated and described, for it is susceptible of embodiment in various other forms, al1 coming wlithin the scope of the following claims.

I c aim:

1. In a core drill, abody having a tubular i v shank providing a circulation water cham- `ber, an imperforate tubular member carinto the discharge Y Chamber,

ried by the -body and extending upwardly into the shank, said tubular member having a closed upper end and providing an indea centrally dis- .extending upwardlyl the body having independent discharge` ports l communicating with the discharge chamber, a tubular core bit aligned with the core barrel, and outer boring cutters carried upon the lower end of the body.

2. In a core drill, a body having a tubular shank providing a circulation water chamber, an imperforate tubular member carried by the body and extending upwardly into the shank, said tubular member ,having a closed upper end and providing an inde- 7 pendent discharge chamber, a centrally disposed core barrel carried lby and extending through the body and upwardly into the discharge chamber, the body having independent discharge ports communicating .S0 with the discharge chamber, a tubular core bit carried by the lower end of the core barrel, and outer borin bits carried upon the lower end of the body. 4

3. In a core drill, a body having a tubular shank providing a circulation l water chamber, an imperforate tubular member carried by the body and extending upwardly into the shank, said tubular member having a closed upper end and providing an independent discharge chamber, a centrally disposed core barrel carried by the body and extending upwardly into the discharge chamber, the bore of the body from theupper end of the body downwardly throughout a major. portion of its length being larger than the vdiameter of the core barrel toprovide an'extension of the dischargechambeqand the body being provided with independent discharge' ports -communicating with said 100 chamber extension, a tubular core bit aligned with the core barrel, and outer boring cut-` ters carried upon the lower end of the body.

4., In a core drill, a body having a tubular shank providing a circulation water cham- 105 ber, an imperforate tubular member carried by the body and extending upwardly into the shank, Said tubular `member having a closed upper end and providing an independent dischargechamber and the body upwardly into ,the discharge chamber, a 1,15

check valve :normally closing the upper end of the core barrel, a tubular corebit aligned with the core barrel,.and outer boring cutters carried upon the lower end of the body.

5. Ina core drill, a body having a central 12d I bore and provided 'with a-tubular shank formingl a circulation water chamber, a core barrel extending through said\bore and 'securedto the body at its lower end with itsupper end a. tubular core bit. carried by the lower end of the core barrel,outer boring cutters carried by the body. and means for preventing communication between the circulation chamber and the upper end of the barrel. 13

portion extending` into the shank, 125 i n 'l tubular member closed at its upper end andvat providing a discharge chamber, al centrally.

disposed core barrel carried by said body member and extending upwardly into the discharge chamber, a tubular core bit aligned with. the core barrel, outer boring cutters carried by the body member, and a--tubular shank detachably connected to the body member and surrounding the tubular member and forming therewith an annular circulation water chamber, the body having circulation ducts directing Vwater from the water chamber to the cutters. and independent discharge ports communicating with the `lower portion of the discharge chamber.

7. In a core drill, the combination of a drill string, a body attached to the lower end of the drill string and having a central bore and a tubular shank,- outer cutters cari'ied by the body, and a tubular core barrel having a tubular core bit at its lower end, the core barrel and said bore having screw lthreads connecting the same, said barrel eX- tending upwardly into the shank and having a closure at its upper end of no larger diameter than the barrel, whereby the drill string may be removed from the well and the barrel and core bit removed as a unit from the drill string by pulling the core barrel downwardly and leaving `the outer cutters in place.

8. In a core drill, .a body having a tubular shank. a core barrel 'carried by the body and extending upwardly into the sh nk, a -central core bit aligned with the core barrel,-

- oppositely disposed boring cutters carried upon the lower end of thebody with their cutting edges extending below its lower surface. the body being cut away on opposite sides to provide*diametrically opposite substantially flat surfaces approximately radially disposed and` extending upwardly from the lower surface of the body, said surfaces being provided with lateral dove-tail ways, the Shanks of the cutters engaging said flat -surfaces and having lateral dove-tail webs engaging in said ways,and means securing each cutter in place.

. well as in the core barrel.

9; Iii a l'core drill, the combination of a body having a central bore and a tubular anda tubular core barrel having a closure of noflarger diameter than the barrel at its upper end, and detacliably secured to said bore at its lower end, said barrel with said closure being removable from the said bore in a downward direction, and extending upwardly into the shank, Said'core barrel being removable fromthe body independently ot' the outer cutters.

l0. In a core drill, al body having a discharge chamber therein. a core barrel extending upwardly from the lower end of the drill i-nto the discharge chamber and having a valve with a central guide stem. the space around the edge of the valve disc being unobstructed to peri'm't water and core ma- -terial to pass from the upper end of the core barrel into the discharge chamber and operating to maintain communication between the interior ot the core barrel and vthe discharge chamber when the valve is drill is pulled upwardly a partial vacuum will be ormed in the discharge chamber as 11. In a core drill, a body having a tubular shank providing a circulation water chamber, an i/niperforate discharge chamber disposed witliin the circulation chamber, a core barrel extending upwardly into the discharge chamber and having a valve at its upper end, a supporting member at the lower end of the 'body supporting the discharge lchamber and the core bai-rel` said supporting member having openings therethrough communicating at the inner ends with the discharge chamber and inclinmg down- -Wai'dlytowards their outer ends whereby when the drill is pulled upwardly a partial vacuum will be formed in the vdischarge chamber as well as in the core barrel.

. Signed at Los Angeles, California, this 4th day of August, 1922. y

ROLAND Ri. CRUM.

shank, outer cutters carried by the body,` 

